Aug 3 2015
Physicians at Boston Children's Hospital have created custom, high-fidelity 3D-printed models of blood vessel malformations together with the closely present normal blood vessels using synthetic resins. They also printed the surrounding brain anatomy in certain cases.
A 3D-printed vein of Galen malformation. (Credit: Boston Children's Hospital)
The research was carried out, for the first time by 3D printing the brain anatomy of four children before undertaking high-risk brain procedures.
The children were known to have cerebrovascular malformations (abnormalities in the brain's blood vessels), which pose great treatment challenges.
"These children had unique anatomy with deep vessels that were very tricky to operate on," says Boston Children's neurosurgeon Edward Smith, MD, senior author of the paper and co-director of the hospital's Cerebrovascular Surgery and Interventions Center.
"The 3D-printed models allowed us to rehearse the cases beforehand and reduce operative risk as much as we could." The children were in the age group of 2 months to 16 years old. Three of the four children suffered arteriovenous malformations (AVMs), which is a condition wherein tangles of veins and arteries have unusual connections. This condition requires surgical treatment.
"AVMs are high-risk cases and it's helpful to know the anatomy so we can cut the vessels in the right sequence, as quickly and efficiently as possible," says Smith. "You can physically hold the 3D models, view them from different angles, practice the operation with real instruments and get tactile feedback."
The 2-month old infant was found with a rare vein of Galen malformation where arteries are directly connected to the veins, by avoiding the capillaries. An interventional radiology technique was performed to treat this malformation by sealing off the malformed blood vessels from inside.
"Even for a radiologist who is comfortable working with and extrapolating from images on the computer to the patient, turning over a 3D model in your hand is transformative," says Darren Orbach, MD, PhD, chief of Interventional and Neurointerventional Radiology at Boston Children's and co-director of the Cerebrovascular Surgery and Interventions Center. "Our brains work in three dimensions, and treatment planning with a printed model takes on an intuitive feel that it cannot otherwise have."
In association with the Boston Children's Hospital Simulator Program (SIMPeds), the enlarged and life-sized 3D models were produced with the help of brain magnetic resonance (MR) and MR arteriography data from each child. The findings showed 98% agreement between the measurements taken from the models and the actual anatomy of the children.
The malformations of all four children were successfully removed without any complications. Upon comparing two of the AVM patients with controls without 3D-printed models in terms of type and size of AVM, age, operating room and surgeon, the surgical time for those with 3D models was reduced by 12% (30mins). (Actual surgical time was 285 and 288 mins for the controls and 254 and 257 mins for the ones with 3D models.) The 30-minute reduction in surgical time is highly important for children who are sensitive to anesthesia.
Smith and Orbach are continuing to use 3D models for their trickier cases. "3D printing has become a regular part of our process," says Smith. "It's also a tool that allows us to educate our junior colleagues and trainees in a way that's safe, without putting a child at risk."
The findings of the research were reported in the Journal of Neurosurgery: Pediatrics.